U.S. patent number 4,027,679 [Application Number 05/711,218] was granted by the patent office on 1977-06-07 for tobacco product.
Invention is credited to Joseph Kaswan.
United States Patent |
4,027,679 |
Kaswan |
June 7, 1977 |
Tobacco product
Abstract
This invention provides a smoke vector for a cigarette, and the
like, for modifying or altering the mainstream smoke at or near the
combustion zone or burning zone. The smoke vector comprises a thin
walled elongated, impervious tube-like member or vector which is
hollow and empty. The vector extends longitudinally through the
cigarette and terminates with an impervious mouth end. During an
indrawn breath by the smoker, the products of the combustion of
tobacco in systemic heat is below the formation temperatures of
temperature dependant hazardous chemicals.
Inventors: |
Kaswan; Joseph (Astoria,
NY) |
Family
ID: |
27064482 |
Appl.
No.: |
05/711,218 |
Filed: |
August 3, 1976 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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534478 |
Dec 19, 1974 |
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Current U.S.
Class: |
131/339;
131/363 |
Current CPC
Class: |
A24D
1/00 (20130101) |
Current International
Class: |
A24D
1/00 (20060101); A24D 001/00 () |
Field of
Search: |
;131/8R,9,1A,1R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Michell; Robert W.
Assistant Examiner: Millin; V.
Parent Case Text
This is continuation-in-part of application Ser. No. 534,478 filed
on Dec. 19, 1974, now abandoned.
Claims
It is claimed:
1. A cigarette which comprises
a. a thin walled, hollow smoke vector, of ceramic or metal
construction, extending longitudinally substantially the length of
and disposed concentrically therewith so as to be surrounded by
tobacco,
b. said vector comprising a substantially impervious hollow and
empty cylindrical member having a substantially impervious closed
mouth end and an open front end,
c. said vector establishing the heat removal sequence during a draw
by collecting draw heat at the point of convergence inside the
vector, creating the highest possible temperature differential
between the open end of the vector and free air outside the vector,
and removing heat by high velocity convection currents,
d. whereby the smoker draws in, during a puff, smoke comprising the
products of the combustion of tobacco in systemic heat, below the
formation temperatures of temperature dependant hazardous
chemicals.
2. A cigarette according to claim 1 wherein said vector is a
refractory oxide.
3. A cigarette according to claim 1 wherein said vector is made of
fused quartz.
4. A cigarette according to claim 1 wherein said vector is made of
stainless steel.
5. A cigarette according to claim 1 wherein said vector comprises a
plurality of segments which may be removed as smoking progresses.
Description
BACKGROUND
This invention relates to a smoke vector for modifying the smoke of
tobacco products. In its more specific aspect, this invention
relates to a smoke vector which mechanically and chemically
modifies and alters the smoke drawn in by the smoker of a cigarette
or the like.
U.S. Pat. No. 3,258,015, dated June, 1966, to Ellis et al.
describes a smoking device which operates to release a nicotine
flavored vapor from a nocotine-releasing material produced by the
smoldering of tobacco when the smoker draws through a tube. It
should be noted that Ellis et al. specifies that none of the
products of combustion are drawn in by the smoker. Notwithstanding
the benefits to the smoker who uses such a device, the annual
increase in the use of cigarettes whose products of combustion are
drawn in by smokers demonstrates a need to protect this latter
group of smokers from the hazardous products of combustion produced
by the cigarettes they smoke.
While this invention is described hereinafter with particular
reference to cigarettes, it should be understood that the invention
is also applicable to cigars and cigarillos as well.
Smoking has become a widespread habit, but in recent years has come
under severe criticism as being dangerous to the smoker's health.
Tobacco smoke is an aerosol comprising gas and semi-liquid
particles measuring from about 0.1 to over 1 micron. The burning
zone has a temperature range of from 875.degree. C. to 1050.degree.
C. Within this temperature range both oxidation by burning and
thermal degradation due to absence of oxygen occur but in different
zones. The high temperature zone is in the axial center and is the
region of thermal degradation of tobacco-- a reductive process.
Adjacent to the burning zone upstream of the burn the products of
combustion and degradation are pyrolized and distilled and the
smoke constituents drawn up the cigarette are re-pyrolized and
re-distilled as the burning zone moves rearward along the
cigarette.
Thus, a number of reactions are occuring such as dehydration,
de-hydrogenization, de-amination, cracking and pyrosynthesis, and
in general, at the center of the burn, thermal degradation.
As a result of thermal degradation and pyrosynthesis, the smoke
inhaled or sucked in by the smoker during a puff, sometimes called
mainstream smoke ", contains numerous chemicals such as paraffins,
low molecular weight carboxyl compounds, amines, pyridine,
terpenes, polyaromatic hydrocarbons, and nicotine as well as carbon
monoxide and particulate matter. Some or many of these chemicals
are harmful to the smoker's health.
In order to diminish this health hazard, cigarettes are commonly
provided with a filter at the upper or mouth end. These filters,
which are well known in the art, remove one or more of these
constituents from the smoke by mechanical or physical means and/or
by absorption, thereby decreasing the amount of harmful matter
drawn in by the smoker. Notwithstanding the effectiveness of these
filters, harmful constituents in the smoke stream are decreased at
best and a substantial amount of these constituents are inhaled by
the smoker. Cigarette filters are, therefore, supportive of efforts
to diminish the hazard to health from smoking, but are not
corrective. Corrective measures require the elimination of harmful
chemicals, not their reduction. In order to eliminate these
chemicals, it is necessary to understand the theory of combustion
of cigarettes which gives rise to their formation. It therefore
would be of value to explain this theory in order to comprehend the
corrective objectives and mechanism of this invention.
It has been established that many harmful chemicals in cigarette
smoke are formed in the high temperature, oxygen-deficient zone
immediately downstream of the burn. This region is commonly known
as the coal. The formation of many of these chemicals is
temperature dependant in this oxygen-deficient zone, being the
products of thermal degradation of tobacco.
Attempts to reduce the temperature of the coal using additives has
met with little success. This is also true of attempts to change
the combustion characteristics of cigarette tobacco.
A more complete understanding of the cigarette as a combustion
system is required to pinpoint the cause and achieve a resolution
to thermal degradation of tobacco.
There are two types of combustion systems. One system is a
stationary-fuel, moving-combustion zone system such as exemplified
by smoldering rope, explosive fuse cord, candles, etc. The other
system is a stationary-combustion zone, moving-fuel type such as
gas burners, welding torches and oil burners. The combustion
characteristics of the burner system are not affected by the
combustion system to which the burner belongs, (although the
stationary combustion-zone, moving-fuel combustion system permits
greater fuel velocities).
Cigarettes are of the stationary-fuel, moving-combustion zone type
of system.
There is a burner system in which the configuration of the burner
has an effect on the combustion characteristics. It is the circular
solid (as differentiated from hollow) combustion system. Circular
burners, as do all burners, release heat in all directions. The
released heat from the perimeter of the circular solid burner moves
outwardly to the surrounding air and inwardly toward the axial
center of the fuel. Adjacent burning points on the perimeter
mutually exclude heat transfer from each other since they are both
burning at the same temperature.
Heat released inwardly is transferred by conduction to the center,
which acts as a collection point for heat from all points on the
burning perimeter. The center, being the point of convergence of
heat, is raised to a temperature substantially higher than any
point on the perimeter.
The center releases its heat wherever it can. Typical directions of
heat release are upward, forming a pre-heating zone for fuel, and
downward for cooling by air, and laterally in all directions. Heat
moving downwardly moves out from the point of convergence, radially
forming a curved conical ember. Heat moving out laterally, moves
out radially toward the burning perimeter. Since the burn itself is
a source of heat, the opposing movement of heat from the point of
convergence and from the burning perimeter, reaches a point of
equilibrium, which, in a round burner, is a circle of equilibrium
concentric with the burning perimeter.
The distance of a point on the circle of equilibrium from a point
on the burning perimeter and the point of convergence of heat is
dependant upon the temperature of the point of convergence and that
of a point on the burning perimeter. The greater the heat of the
coal in relation to a point on the perimeter, the closer the circle
of equilibrium will be to the perimeter; conversely, the lower the
heat of the coal, the closer will be the position of the circle of
equilibrium to the coal.
Heat from any point on the burning perimeter radiated outwardly is
determined by the temperature in the zone toward which the heat is
moving. Thus, adjacent points on the burning perimeter mutually
exclude heat transfer from one another since they are both at the
same temperature. Additionally, the higher the temperature of the
circle of equilibrium or the closer the circle of equilibrium to
the burning perimeter, the less heat will move inward from the
burning perimeter and the more heat will move outward from it. The
outward release of heat from the burning perimeter warms and
rarifies approaching air, thereby depleting the oxygen supply
available for combustion.
The proximity of the circle of equilibrium to the burning
perimeter, then, is a determinant of the rate of combustion. The
temperature of the coal, being a determinant of the circle of
equilibrium, is a determinant of the rate of combustion, and a
secondary determinant of the rarefaction of approaching air and its
percentage supply of oxygen for burning.
In all of the above, cigarettes behave as typical circular solid
(as opposed to hollow) combustion systems. While the cigarette
tobacco smolders, side stream smoke shows heat being released to
air; while below the burn, the glowing ember maintains a constant
length as the burn moves backward along the fuel. The constant
length of the glowing ember is an indication of the existence of
equilibrium between heat produced and heat released during the
smolder.
During smolder, both heat produced by burning and heat removed by
ambient air at the face of the ember, proceed at atmospheric
pressure in ambient air. The rate of heat removal from the coal
determines the temperature of the coal and the proximity of the
circle of equilibrium to the burning perimeter, and in turn the
rarefaction of approaching air by the heat of the burn, and
therefore the rate of burning. By itself, therefore, a cigarette
smoldering arrives at a constant rate of burning, and this is in
equilibrium with the rate of cooling.
The effect of smoldering upon the cigarette as a solid circular
combustion system is different from what the effect would be on a
hollow circular combustion system. The cigarette, when smoldering,
behaves as a typical solid circular combustion system in that heat
from the burning perimeter moves in to the center and converges
there, with the result that the fuel (tobacco) is raised to an
exponentially higher temperature than any segment of the circle.
For purposes of convenient identification this heat at the point of
convergence can be called systemic heat since it is due to the
characteristics of the combustion system to which the cigarette
belongs.
When a smoker takes a puff and draws in smoke, he sharply increases
the velocity of air moving into the burning perimeter by suction.
Rarefaction of approaching air is overcome and the rate of burning
is greatly accelerated. The smoker's draw upsets the equilibrium
maintained by the cigarette in smolder by altering the condition
that produce it.
Since the rate of cooling proceeds at atmospheric pressure in
ambient air, the accelerated burn rate produces more heat than can
be released in the same atmospheric conditions as smolder in the
same increment of time as the draw. Thus, the heat release
mechanism is overwhelmed during the draw.
Since the atmosphere cannot absorb the heat as quickly as it is
produced during a draw, there is a time delay for release of heat.
During this time delay more heat is being added by the rest of the
draw to the heat not yet released because of the time delay. This
causes a rise in temperature above the already high temperature of
systemic heat.
This additional heat rise is sufficient to cause the tobacco in the
center holding the heat to decompose. The products of this
decomposition are harmful to the smoker. For purposes of convenient
identification, heat rise caused by delay in heat release during a
draw can be called draw heat.
In order to prevent the thermal decomposition of tobacco into
products harmful to the smoker it is necessary to prevent the
tobacco from reaching the temperature of decomposition. This can
only be accomplished by preventing the coupling of systemic heat
with draw heat.
It is the object of this invention to redirect the draw heat more
quickly to the atmosphere thus precluding a time delay for release,
thereby preventing coupling draw heat with systemic heat.
The ambient air that surrounds a burning cigarette absorbs the
heat. The air molecules absorb the heat at essentially a fixed
rate: each molecule absorbs a fixed amount of heat. The increased
molecular activity caused by the absorption of heat causes the air
envelope to expand and move away from the source of heat, while
cooler air moves in to replace the expanding air. In a continuing
system, this becomes a preferential direction of flow.
In a circular system such as a cigarette, the movement of cool air
into the combustion zone is radially inward. This radial movement
has the effect of narrowing the space in which the hot expanding
gas is moving away. The net effect is to force the expanding gases
into a column, while at the same time increasing the axial outward
flow velocity of the hot gases.
The higher the temperature of the source of heat relative to the
surrounding air the greater the amount of molecules will be needed
to remove the heat, and therefore the greater the volume of air to
contain the greater amount of molecules. This is accomplished
spontaneously in free air by increased velocity of convection
currents to bring a greater amount of cool air across the face of
the heat source.
It is advantageous, therefore, to make use of the added air flow of
convection currents by increasing the temperature differential
between the end of the cigarette and the atmosphere.
In cigarettes, as they are currently manufactured, systemic heat
moves from the point of convergence radially outward in all
directions by conduction. There are temperature gradients between
the point of convergence and the greater outside face of the ember
meeting the air. There is also a temperature drop from the coal to
the outside face due to distribution of heat to a greater total
area.
The resulting temperature drop and point by point distribution of
heat on the outside face of the ember results in a lowered
temperature differential between any one point and the atmosphere.
This low differential is the determinant for convection current
velocity. By reason of this invention the smoke vector provides the
means to increase the temperature differential between the end of
the cigarette and the atmosphere thus accelerating convection
currents and drawing cool air to the end of the cigarette for
accelerated heat removal.
Accelerating heat removal will have the effect of preventing
coupling of draw heat to systemic heat thereby preventing the
decomposition of tobacco in the coal into harmful chemicals.
THE INVENTION
The invention comprises a thin walled cylinder or smoke vector
disposed in the longitudinal axis of the cigarette. The cylinder or
vector is sealed at the mouth end and open at the front end, and it
is substantially impervious relative to the draw strength of the
smoker. The vector is made of an inert material and desirably may
be segmented for removal of unneeded sections as the cigarette
burns down. Further, the vector exhibits a relatively high specific
heat so as to be essentially transparent to heat whereby there is
established a preferentail direction of flow of heat from the
burning tobacco through the wall of the vector to the air inside
the tube.
In order to maintain the largest differential in heat between the
air in the tube and the air outside the cigarette it is essential
that heat transported through the wall of the vector be transferred
directly to air and that there be no material between the interior
wall of the vector and the air inside the vector which might absorb
heat, since any absorption of heat would lower the differential
between the high temperature inside the vector and the free air
outside the cigarette. Thus, air inside the vector is in direct
contact with all points of the interior wall of the vector with
nothing else interposed.
With this construction, the preferential direction of flow is
established as a venturi effect, accomplishing a temperature
decrease in the coal.
During a draw, heat added to the point of convergence will first
impinge the outer face of the vector and then pass readily by
conduction to the inner face of the cylinder. The heated interior
walls of the cylinder will be raised to a high temperature as the
point of convergence of heat. With the increase of heat during the
draw the air inside the cylinder will increase in temperature
creating a larger differential with respect to the free air outside
the open end of the vector. This increased differential will
accelerate both the movement of heated air away from the open end,
and the radial movement of cool air inward to replace the warmed
air, thus maintaining atmospheric pressure. This continuous and
accelerated flow will remove the heat added to the cigarette by the
increased rate of burning during the draw and prevent the coal from
reaching the temperature of thermal decomposition.
This invention together with other objects may be best understood
by referring to the following detailed description, and the
drawings in which:
FIG. 1 is a cross-sectional view of a cigarette showing the smoke
vector of this invention;
FIG. 2 is front end view of FIG. 1; and
FIG. 3 is an alternative embodiment of the invention.
Broadly my invention for a smoke vector comprises a longitudinally
disposed insert extending substantially the length of the
cigarette. The smoke vector is concentrically arranged in the body
of the cigarette so as to be surrounded by tobacco. It is essential
that the vector be sealed at the mouth end and be open at the front
end in order to establish the proper convection currents so that
the coal will remain below its thermal decomposition temperature as
explained above.
In order to describe the invention in greater detail, reference is
now made to the drawings wherein like reference numerals designate
similar parts throughout. The ciarette, shown generally by the
numeral 10, is provided with a typical paper wrapper 12 as the
outer shell to encase the tobacco 14. Smoke vector 16 extends
longitudinally through the center of the cigarette so as to be
concentrically arranged therewith. The vector extends from the
front or burning end to the upper or mouth end of the cigarette so
as to be substantially coterminous with the wrapped tobacco. The
vector is sealed or capped with a substantially impervious cap
member or seal 17 at the mouth end.
The vector 16 may be formed of a ceramic or metal structure, for
example, and must be capable of withstanding the temperature of
burning of a cigarette and may include, for example, fused quartz,
or stainless steel. The vector can be of granular construction and
be pressed or molded to shape, or may be held together with high
temperature cement or the vector may be made of rigidized foam. The
advantage of granular or rigidized foam construction is that as the
cigarette burns down the used portion of the vector may be tapped
off making the shortened remaining vector more efficient. The
vector desirably may have dimensions of 2 1/2 or 3 millimeters in
diameter, and have a wall thickness that may vary from 1/3
millimeter to 1 millimeter. The empty center of the vector may be
1/2 millimeter to 1 and 1/3 millimeter. Variations in performance
may be accomplished by varying the outside diameter and wall
thickness of the vector.
Cigarette 10 may be provided with a conventional mouthpiece (not
shown) formed of a substantially impervious material such as paper,
to prevent the intake of air when the smoker draws on the
cigarette. The mouthpiece spreads and cools the indrawn smoke and
may also include a filter for smoke.
According to the embodiment shown in FIG. 3, the smoke vector 20 is
a cylinder or tube comprising a plurality of segments extending
beyond the tobacco that may be tapped off. In this manner, the
unneeded portion of the smoke vector is continuously removed, and
the remaining vector kept efficient.
Although the vector is preferentially of circular cross section, as
is the preferential shape of cigarettes, the vector may be of any
desired configuration such as elliptical.
It will be observed that the smoke vector has the distinct
advantage of providing a technical and economic means for modifying
or altering smoke so that it is less harmful to the smoker. The
mainstream smoke is modified to less harmful chemicals during
pyrolisis or distillation. Certain harmful chemicals may be
prevented from forming, while others may be changed, if formed,
during combustion.
It will be understood that the smoke vector described may be varied
without departing from the invention.
* * * * *